The aim of this project is to identify and evaluate potential DNA repair inhibitors by an in-depth search of the literature; to find out if specific mechanisms exist for DNA repair inhibition; and to evaluate whether this information can be practically applied. The study includes a comprehensive review of interference with DNA repair by chemical, physical, and genetic factors. Cell death, delayed lethality, loss of proliferative capacity, and mutagenesis are expressions of unrepaired DNA changes, misrepaired nucleotide sequences, delayed repair, or copying errors during the semi-conservative DNA replication in the cell cycles following the application of a mutagenic agent. It has been shown that DNA repair may be interfered with through different biochemical mechanisms depending on the type of DNA damage and the interfering agent. One new development is the role of poly (ADP-ribose) polymerase in the repair process as a suppressor of DNA synthesis, providing critical time for repair to take place prior to DNA replication. Interference with DNA repair is one of several mechanisms proposed to explain co-mutagenicity.